Syndromes of thrombotic microangiopathy George, James N; Nester, Carla M
The New England journal of medicine,
08/2014, Letnik:
371, Številka:
7
Journal Article
Recenzirano
This review article covers the diverse pathophysiological pathways that can lead to microangiopathic hemolytic anemia and a procoagulant state with or without damage to the kidneys and other organs.
All Things Complement Thurman, Joshua M; Nester, Carla M
Clinical journal of the American Society of Nephrology,
10/2016, Letnik:
11, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The complement (C) cascade is an ancient system of proteins whose primary role is to initiate and modulate immune responses. During C activation, circulating proteins are cleaved and nascent cleavage ...fragments participate in a broad range of downstream innate and adaptive immune functions. Although the majority of these functions are either homeostatic or protective, a large body of experimental and clinical evidence also highlights a central role for the C system in the pathogenesis of many types of glomerular disease. From classic pathway activation in lupus nephritis to alternative pathway dysregulation in C3 glomerulopathy, our understanding of the spectrum of C involvement in kidney disease has expanded greatly in recent years. However, the characteristics that make the glomerulus so uniquely susceptible to C-mediated injury are not fully understood, and this remains an area of ongoing investigation. Several C inhibitors have been approved for clinical use, and additional C inhibitory drugs are in development. The use of these drugs in patients with kidney disease will expand our understanding of the benefits and limitations of C inhibition.
The Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for the Management of Glomerular Diseases is an update to the KDIGO 2012 guideline. The aim is to assist clinicians ...caring for individuals with glomerulonephritis (GN), both adults and children. The scope includes various glomerular diseases, including IgA nephropathy and IgA vasculitis, membranous nephropathy, nephrotic syndrome, minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), infection-related GN, antineutrophil cytoplasmic antibody (ANCA) vasculitis, lupus nephritis, and anti–glomerular basement membrane antibody GN. In addition, this guideline will be the first to address the subtype of complement-mediated diseases. Each chapter follows the same format providing guidance related to diagnosis, prognosis, treatment, and special situations. The goal of the guideline is to generate a useful resource for clinicians and patients by providing actionable recommendations based on evidence syntheses, with useful infographics incorporating views from experts in the field. Another aim is to propose research recommendations for areas where there are gaps in knowledge. The guideline targets a broad global audience of clinicians treating GN while being mindful of implications for policy and cost. Development of this guideline update followed an explicit process whereby treatment approaches and guideline recommendations are based on systematic reviews of relevant studies, and appraisal of the quality of the evidence and the strength of recommendations followed the “Grading of Recommendations Assessment, Development and Evaluation” (GRADE) approach. Limitations of the evidence are discussed, with areas of future research also presented.
In both atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) complement plays a primary role in disease pathogenesis. Herein we report the outcome of a 2015 Kidney Disease: Improving ...Global Outcomes (KDIGO) Controversies Conference where key issues in the management of these 2 diseases were considered by a global panel of experts. Areas addressed included renal pathology, clinical phenotype and assessment, genetic drivers of disease, acquired drivers of disease, and treatment strategies. In order to help guide clinicians who are caring for such patients, recommendations for best treatment strategies were discussed at length, providing the evidence base underpinning current treatment options. Knowledge gaps were identified and a prioritized research agenda was proposed to resolve outstanding controversial issues.
Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy caused by uncontrolled activation of the alternative pathway of complement at the cell surface level that leads to ...microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney failure. In approximately one half of affected patients, pathogenic loss-of-function variants in regulators of complement or gain-of-function variants in effectors of complement are identified, clearly implicating complement in aHUS. However, there are strong lines of evidence supporting the presence of additional genetic contributions to this disease. To identify novel aHUS-associated genes, we completed a comprehensive screen of the complement and coagulation pathways in 36 patients with sporadic aHUS using targeted genomic enrichment and massively parallel sequencing. After variant calling, quality control, and hard filtering, we identified 84 reported or novel nonsynonymous variants, 22 of which have been previously associated with disease. Using computational prediction methods, 20 of the remaining 62 variants were predicted to be deleterious. Consistent with published data, nearly one half of these 42 variants (19; 45%) were found in genes implicated in the pathogenesis of aHUS. Several genes in the coagulation pathway were also identified as important in the pathogenesis of aHUS. PLG, in particular, carried more pathogenic variants than any other coagulation gene, including three known plasminogen deficiency mutations and a predicted pathogenic variant. These data suggest that mutation screening in patients with aHUS should be broadened to include genes in the coagulation pathway.
Licht et al. present the 2-year follow-up data of the landmark trials studying the efficacy of eculizumab in the treatment of atypical hemolytic uremic syndrome (aHUS). They report sustained ...improvements in hematologic parameters, continued safety, and additional improvements in kidney function with extended treatment. This report adds a layer of comfort to our care of patients with this rare disease; however, it is unlikely to be the final chapter in the treatment of aHUS.
Membranoproliferative glomerulonephritis (MPGN) denotes a general pattern of glomerular injury that is easily recognized by light microscopy. With additional studies, MPGN subgrouping is possible. ...For example, electron microscopy resolves differences in electron-dense deposition that are classically referred to as MPGN type I (MPGN I), MPGN II, and MPGN III, while immunofluorescence typically detects immunoglobulins in MPGN I and MPGN III but not in MPGN II. All three MPGN types stain positive for complement component 3 (C3). Subgrouping has led to unnecessary confusion, primarily because immunoglobulin-negative MPGN I and MPGN III are more common than once recognized. Together with MPGN II, which is now called dense deposit disease, immunoglobulin-negative, C3-positive glomerular diseases fall under the umbrella of C3 glomerulopathies (C3G). The evaluation of immunoglobulin-positive MPGN should focus on identifying the underlying trigger driving the chronic antigenemia or circulating immune complexes in order to begin disease-specific treatment. The evaluation of C3G, in contrast, should focus on the complement cascade, as dysregulation of the alternative pathway and terminal complement cascade underlies pathogenesis. Although there are no disease-specific treatments currently available for C3G, a better understanding of their pathogenesis would set the stage for the possible use of anti-complement drugs.
When a pregnant or postpartum woman presents with sudden and severe microangiopathic hemolytic anemia (MAHA) and thrombocytopenia, three syndromes that require urgent care must be considered: (1) ...preeclampsia with severe features/hemolysis, elevated liver function tests, low platelets (PE/HELLP) syndrome; (2) thrombotic thrombocytopenic purpura (TTP); and (3) complement-mediated thrombotic microangiopathy (C-TMA; also referred to as atypical hemolytic-uremic syndrome). The distinction among these three syndromes is often unclear because they share multiple clinical features. Overlap between PE/HELLP syndrome and the other two syndromes is also apparent from the fact that pregnancy can be a trigger for both TTP and C-TMA both before and after delivery and also the increased frequency of PE/HELLP syndrome in women who have recovered from TTP. When diagnostic criteria for PE/HELLP syndrome are present, management of hypertension and delivery is curative. Absence of improvement or actual progression of MAHA, thrombocytopenia, and kidney function abnormalities after delivery requires consideration of TTP and C-TMA. Minimal kidney involvement with severe thrombocytopenia suggests TTP and the need for treatment with plasma exchange; progressive kidney injury (in the absence of a cause for acute tubular necrosis) suggests C-TMA and the need for anti-complement treatment. We describe how we use these criteria to evaluate and manage pregnant/postpartum women with MAHA and thrombocytopenia.
Atypical aHUS: State of the art Nester, Carla M.; Barbour, Thomas; de Cordoba, Santiago Rodriquez ...
Molecular immunology,
09/2015, Letnik:
67, Številka:
1
Journal Article
Recenzirano
•aHUS is an ultra-rare group of diseases defined by thrombocytopenia, anemia and renal failure.•The majority of patients have genetic abnormalities that impair cell surface control of ...complement.•Eculizumab, a monoclonal antibody to C5, has drastically reduced the mortality aHUS.•Long-term therapy for aHUS requires further study.
Tremendous advances in our understanding of the thrombotic microangiopathies (TMAs) have revealed distinct disease mechanisms within this heterogeneous group of diseases. As a direct result of this knowledge, both children and adults with complement-mediated TMA now enjoy higher expectations for long-term health. In this update on atypical hemolytic uremic syndrome, we review the clinical characteristics; the genetic and acquired drivers of disease; the broad spectrum of environmental triggers; and current diagnosis and treatment options. Many questions remain to be addressed if additional improvements in patient care and outcome are to be achieved in the coming decade.
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